Valve system for prosthetics

ABSTRACT

A valve system regulates the air pressure in the space(s) between a residual limb, or liner-covered limb, and a hard socket of an external prosthesis, for example, for improving donning and doffing the prosthesis, and/or during walking and other normal use of the prosthesis. The valve system may include a manually-controlled air outlet and inlet valve that may be installed on a distal region of a hard socket, and/or an automatic one-way outlet valve. The manually-controlled valve is preferably opened and closed by twisting of a handle portion of the valve system, wherein partial rotation of the handle portion relative to the base portion of the valve system creates slight separation of the handle and base portions to form a gap through which may pass air from the well of the socket. This simple twisting, or partial rotation, provides a valve that stays open hands-free, so that the wearer may open the valve and then use his/her hands to don or doff the prosthesis. The manual valve may include a system for preventing the handle and base from becoming entirely separated during normal use, which preferably is a snap-fit of the base onto the handle that retains the ability of the handle and base to rotate relative to each other, and a stop(s) that limit(s) the amount of relative rotation of the handle and base portions of the valve. Opening and closing of the manual valve may be accomplished by a ramp system, so that, upon rotation of the handle in one direction, the handle comes close to, and seals with, the base, and upon rotation of the handle in the opposite direction, the handle becomes slightly distanced from, and unsealed from, the base.

This application is a continuation of Non-Provisional application Ser.No. 12/364,511, filed Feb. 2, 2009 and issuing on Aug. 9, 2011 as U.S.Pat. No. 7,993,413, which claims benefit of Provisional Application Ser.No. 61/024,913, filed Jan. 31, 2008 and which is a continuation-in-partof Non-Provisional application Ser. No. 11/527,752, filed Sep. 24, 2006,now abandoned, which claims benefit of Provisional Application Ser. No.60/719,785, filed Sep. 24, 2005, the entire disclosures of which areincorporated herein by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to prosthetics, and more specifically to avalve system for air release from an external prosthetic such as may beused on a residual limb.

2. Related Art

Gravitational and other forces tend to cause separation between aprosthetic limb and a residual limb. This happens, for example, duringthe swing phase of the gait, when a prosthetic leg is additionallysubjected to centrifugal forces. The manner in which an artificial limbis suspended and/or attached to the residual limb determines the amountof control an amputee has over the prosthesis. Patients have routinelyworn a variety of belts, straps, cuffs and harnesses to prevent theprosthetic limb from separating from the residual limb, but such devicesare inconvenient and tend to cause chafing against the patient's body,giving rise to sores and abrasions.

It has long been appreciated that differential air pressure, oftenreferred by those of skill in the art as “suction,” may be utilized toretain or suspend, or assist in retaining or suspending, a prostheticlimb on a patient's residual limb. “Suction suspension” typicallyinvolves a hard socket and a cooperating liner positioned between theresidual limb and the prosthetic socket. The liner is rolled onto theresidual limb for a suction, slight compression, and/or grippingconnection of the inner gel layer (or otherwise tacky layer) of theliner to the skin of the residual limb. The liner-covered limb is theninserted into the prosthetic socket, and the outer surface/layer of theliner preferably forms a suction, grip, or other interference fit to thesocket to interfere with the socket falling off the limb.

Said “suction” fit between the liner and the socket, due to the materialand texture of today's preferred liner as further discussed below, maymore accurately be referred to as a “partial-suction” fit. In such a“partial-suction” fit, the outer surface of the liner and its close fitwith the interior surface of the socket will provide significantresistance to air entering the socket from outside the socket (via thetop opening of the socket). Still, because today's preferred liners donot form a true air-tight seal with the socket, some air will slowlyenter the socket, especially during the swing portion of the wearer'sgait and during periods of relative inactivity.

Socket liners frequently have been called “suction liners,” “gelliners,” “roll-on liners” or “suspension liners” and include the “firstgeneration” of gel-layer-only liners, and also the modern “secondgeneration” liners currently preferred by most wearers of prosthetics.These modern liners “second generation” liners typically comprise a thintextile/fabric outer layer that is fixed to the gel-like inside layer.Thus, the second generation of liners is similar to the first generationin its connection to the residual limb, but its connection to, orcooperation with, the socket is Modified by the presence of thetextile/fabric layer. The term “suction liner” began with the firstgeneration liners, which featured the gel layer contacting both theresidual limb (liner's inner surface) and the socket (liner's outersurface), and which, therefore, could be used to create a fairly highamount of pressure differential between the inside of the socket (in the“well” of the socket) and the surrounding ambient air. The terms“suction liner” and “suction socket” are still used by manymanufacturers, prosthetic technicians, insurance and medicare/medicaidentities, and wearers of prosthetics, even though the modern liners,with their textile/fabric outer layers, typically do not form what wouldbe called “true” or “pure” suction with the socket, as further discussedbelow. See the discussion of suction liners in Janusson, et al. (U.S.Pat. No. 6,706,364) and Janusson, et al. (U.S. Pat. No. 6,626,952).

Preferred socket liners are usually fabricated from silicone, urethane,or other gel-like material that grips the limb to such an extent thatthey need to be rolled-onto the limb from a rolled-up “doughnut” form,rather than pulled on like a sock. When rolled-on, there is little, ifany, air remaining between the inner surface of the roll-on liner andthe limb, and the roll-on liner is snug against the limb all the wayaround the circumference of the limb. Also, the inner surface of theroll-on liner is of such material and tacky texture that air will not beable to, or be very unlikely to, enter between the roll-on liner andlimb. Thus, the roll-on liner may be said to form a suction fit and/or aslight compression fit with the limb. A distal force on the liner, suchas caused by the swing of a gait with a prosthetic leg, may tug on theroll-on liner but typically does not loosen, lower, or remove the linerfrom the limb.

The hard socket is usually laminated or otherwise fabricated frompolyethylene, polypropylene, or other copolymers, for example, and isdonned over the liner and the residual limb. A suction-fit, including apartial-suction fit, as discussed above, may form between theliner-sheathed limb and the interior of the socket. A “true” suction fit(allowing high suction, greater amount of vacuum) will be more likely toform if the liner exterior surface is smooth and flexible enough toconform to the contours of the residual limb, for example,non-air-permeable material such as the silicone, urethane, or otherrubbery or gel-like material such as described above for theliner-to-limb connection; if the interior surface of the socket is alsosmooth and non-air-permeable; and, of course, if the socket has noun-sealed holes or apertures.

A “partial” suction fit (allowing lower suction, low amount of vacuum)is more likely to form if one of these conditions is not met, forexample, if the outside of the liner is the thin fabric or other wovenmaterial bonded to a rubbery/gel-like interior layer of the liner, forexample, as described above for “second generation” liners. In such acase, some air will tend to leak through or past the fabric layer of themodern liners into the well of the socket, that is, between the linerand the socket interior surface, so that there is typically not a trueair-tight seal between the two. However, the air leaks fairly slowlybecause of the preferred close fit between the contour of theliner-cover limb and the contour of the internal surface of the socket.This slow air leakage and close fit typically allow their to be a“partial” suction fit between the socket and the liner outer surface,and this “partial” suction fit tends to be more comfortable for manywearers that a “true” or “full” suction fit. In other words, atextile/fabric-covered liner and the resulting “partial” suction tendsto be more comfortable than the stronger “tugging” on the residual limbcreated by the “full” suction of first generation, gel-layer-only liner.The air that slowly leaks into space(s) in between the socket and theliner tends to be expelled with each step due to the force of theresidual limb pushing into the socket. This way, modern, fabric-coveredroll-on liners still tend to create some pressure differential betweenthe well of the socket and the ambient air.

Therefore, many of skill in the field of prosthetics still apply theterm “suction” to a fit or suspension of the prosthetic to the limbranging from excellent suction (with a “true” seal, large resistance toequalization of pressure between the inside and the outside of thesocket) to slight suction (with a “partial” seal, small resistance tosaid equalization such as in many popular liners). Therefore, the terms“suction,” “suction-fit,” and “suction suspension” herein are thereforenot limiting to a particular amount of pressure differential, but to thegeneral process known well in this field of providing a “roll-on” lineror other “interference” liner that helps keep a socket on a residuallimb while creating at least a small amount of blockage/hindrance to airfreely moving in and out of the socket well past the residual limb.

Therefore, it may be said that any region or amount of negative pressurein the space(s) between the liner-sheathed stump and the interior of thesocket, relative to ambient (outside of the socket), may help to holdthe prosthesis upon the limb during use. Certainly, more suction is moresecure than slight suction, but there may be comfort sacrifices thatresult from more suction, for example, chaffing or pulling on the limb.A high-suction prosthesis suspension system may cause the user adiscomforting disturbance of circulation in the limb on which theprosthesis is worn, due to the build up of a high degree of partialvacuum during walking, particularly in warm humid weather. Therefore, avery popular conventional roll-on liner is one such as the Ohio WillowWood Alpha™ liner, which has multiple layers, that is, arubbery/gel-like inner layer and a thin fabric outer layer bonded to theinner layer, so as to moderate the suction to a reasonably effectiveamount without allowing the great forces on the limb that can resultfrom a high amount of suction. A “suction liner” or “roll-on liner”suspension, even in moderate range of suction provided by the preferredliners, gives the patient the ability to better control the prosthesisand provides for useful sensory or proprioceptive feedback. This isbecause there is a more intimate connection between the limb and theprosthetic, over much of the surface area of the limb, compared toold-fashioned waist belts, distal locks, or other methods. Suction orroll-on liner suspension also make a prosthesis feel lighter as comparedto other forms of suspension.

A valve system may be used in combination with a suction/roll-onsuspension system in order to regulate the air pressure in the socket,so that undesirable pressure differentials do not prevent or complicatethe donning and doffing of the socket. Conventional valves aim atrelieving buildup of pressure when the lined limb is inserted into thesocket, which is typically a snug fit by design, to prevent a positivepressure inside the socket relative to outside of the socket (ambientair) and therefore to allow donning.

Because the typical valve system is a one-way valve, or “check valve”that only allows air to be expelled from the socket, it is intended tomaintain a slight negative pressure (slight, partial suction) relativeto ambient once the socket has been fitted on the residual limb andused. The process of walking and other weight-bearing will tend to pushthe limb further into the socket, but the swing portion of the gait willtend to pull the socket off the limb. The pushing of the limb furtherinto the socket may cause the valve to allow air to be expelled, and thepulling of the socket during the swing portion of the gait will tend tocreate suction in the socket because the valve will not allow air toenter the socket through the valve.

In applications wherein the multi-layer roll-on liner allows air toslowly leak into the socket well, as discussed above, or wherein a seam,connection, lock or other aperture in the socket allows air to leak intothe socket, weight-bearing steps will tend to expel air from inside thesocket through the valve and then said leaking will tend to replace atleast some of it (especially on the swing of the gait). Therefore, thereMay be frequent opening and closing of the valve, perhaps for each, orfor many, of the user's steps. Many conventional valves for theseapplications are known to either not work very well, to plug easily, orto make embarrassing noise with each step as the air is expelled.

There are many valve systems in use in the market. Typical valve systemsuse an inner base that passes from the inside of the socket to theoutside of the socket. The outer housing and the valve are then threadedonto the inner base or threaded to the socket wall in an attempt tocreate an air-tight seal between the valve and the socket wall. Suchsystems require a generally flat socket wall surface for installing thevalve and outer housing to prevent air from leaking out of the socketaround the outer housing instead of being expelled through the valve atthe desired air pressure determined by the one-way valve structure.

Issued patents and patent publications relating to valve systems arelisted as follows: Underwood (U.S. Pat. No. 1,586,015), Catranis (U.S.Pat. No. 2,530,285), Sharp et al. (U.S. Pat. No. 2,533,404), Hauser(U.S. Pat. No. 2,790,180), Edwards (U.S. Pat. No. 4,010,052), Carrow(U.S. Pat. No. 4,106,745), Greene (U.S. Pat. No. 5,201,774), Hill (U.S.Pat. No. 5,490,537), Hill (U.S. Pat. No. 5,709,017), Slemker et al.(U.S. Pat. No. 6,287,345), Perkins (U.S. Pat. No. 6,334,876), Hoerner(U.S. Pat. No. 6,361,568), Caspers (U.S. Pat. No. 6,508,842), Laghi(U.S. Pat. No. 6,544,292), Caspers (U.S. Pat. No. 6,761,742), Abrogastet al. (U.S. Pat. No. 6,797,008), Caspers (U.S. Publication No.2004/0181290), and Patterson et al. (U.S. Publication No. 2004/0260403).

SUMMARY OF THE INVENTION

The present invention is a valve system for helping to regulate the airpressure in the space(s) between a residual limb, or liner-covered limb,and a hard socket of an external prosthesis. The valve system may beused to regulate said air pressure for improved donning and doffing theprosthesis, and/or during walking and other normal use of theprosthesis.

The preferred valve system comprises a manually-controlled air outletand inlet valve that may be installed on a distal region of a hardsocket, and/or an automatic one-way outlet valve. Themanually-controlled valve may be used to open the socket well to theoutside air by providing an air passage from a distal region of thesocket well, so that, when the wearer inserts his/her residual limb intothe socket, air is pushed out through the manual valve rather thanbuilding up pressure inside the socket. Also, when a user wishes to doffthe prosthetic, he/she may manually open the valve to allow air to flowthrough the valve into the socket, equalizing the air pressure insideand outside the socket, for easier removal of the limb.

The manually-controlled air outlet and inlet valve is preferably openedand closed by twisting of a handle portion of the valve system, whereinpartial rotation of the handle portion relative to the base portion ofthe valve system creates slight separation of the handle and baseportions to form a gap through which may pass air from the well of thesocket. This simple twisting, or partial rotation, allows sure andrepeatable control of the valve wherein the valve stays in either theopen or closed position without the user's hand holding the valve inthat position. Thus, after opening the manual valve, the valve stays inhands-free open status, while the wearer may use his/her hands to don ordoff the prosthesis. The manual valve preferably comprises a system forpreventing the handle and base from becoming entirely separated duringnormal use, so that the handle portion does not fall off of theprosthesis. Also, the manual valve preferably comprises a stop (s) thatlimit(s) the amount of relative rotation of the handle and base portionsof the valve, so that the user need only rotate the handle a smallamount, for example, less than 90 degrees, to affect opening or closingthe valve. The stop(s) may be part of the system for preventing thehandle and base from entirely separating, or may be provided in additionto said system for preventing.

In one embodiment, the valve system comprises only said manual valve,while in another embodiment, the valve system comprises both a manualvalve and also an automatic one-way air outlet valve. In yet another,less-preferred embodiment, the valve system may comprise only theautomatic one-way air outlet valve.

In embodiments comprising the automatic air outlet valve; said automaticvalve is a “one-way” or “check” valve, with a valve stem that “pops” orotherwise opens consistently and quietly at a small differentialpressure, for example, a pressure inside the socket (in the distalspace(s) between said socket and the limb or liner-covered limb) that is≦3 psi pressure above ambient pressure (outside the socket).

The valve system, whether it includes only a manual valve, both manualand automatic valves, or only an automatic valve, are preferablyadhesively mounted on the outside of the socket. Thus, the valve systemis easier to mount than conventional valves due to this preferredadhesive mounting and due to preferably no part of the valve beinginstalled from the inside of the socket. The preferred valve system hasno threaded attachment to the socket, and no portion that extends intothe hard socket. The preferred valve system comprises a base portionthat is installed on or near the outside surface of the hard socket,preferably without threaded connection between the base and the hardsocket. A hole is drilled in the hard socket from the outside surface ofthe socket to the inside surface of the socket, to align the hole in thesocket with the bores/passages in the valve system. The other portionsof the valve system, for example, the handle and the optional one-wayvalve structure, are then connected to the base portion, without saidother portions requiring any contact with, or direct attachment to, thehard socket. Said other portions may be removable for cleaning,replacement of o-rings or other seals, and/or for other maintenancewithout removing the base from the hard socket.

The inventors envision, however, that features of the invented valvesystem may also be incorporated into a valve that is attached to a hardsocket by other means than are discussed herein as being preferred. Forexample, conventional mounting systems for air expulsion valve in theindustry, as discussed in the Related Art section above, may allow avalve with some of the invented features of the present invention to beused in a format wherein the valve is connected to a base that protrudesor resides inside the hard socket.

In embodiments comprising a one-way air outlet valve, the one-way valvestem may have a polygonal side wall, or have other recesses or groovesin its side wall(s) to create passages through which air may flowquietly. Alternatively, the valve stem may be cylindrical and thechannel in which the valve stem slides (the valve housing bore) may bepolygonal or have recesses or grooves in its wall(s), to create passagethrough which air may flow quietly. Or, both valve stem and the housingbore may be non-cylindrical. The preferred low-profile,external-mounting of the valve, and the quieter action of, and quieterair flow from, the one-way valve as it “pops” and expels air frequentlyduring walking, may result in a less intrusive and less noticeableapparatus than is more acceptable and less embarrassing to wearers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a hard socket and liner combination,wherein one embodiment of the invented valve is shown attached to theoutside of the hard socket. In this view, the liner is shown as spacedfrom the socket, but it will be understood from the foregoingdiscussion, that the liner and socket will tend to be in close contactfor at least part of the length along the socket and preferably allaround the circumference of the liner and socket at or near the top(proximal region) of the socket. Some space between the liner-coveredlimb distal end and the socket interior surface distal end is normallypresent, so that the limb does not reach all the way to the distal endof the well of the socket.

FIG. 1B is a schematic view of a hard socket holding a residual limbwith second generation roll-on liner, with one embodiment of theinvented valve system installed on the hard socket distal portion. Thisview illustrates more accurately the preferred relationship of residuallimb, roll-on liner, socket and valve.

FIG. 1C is a schematic cross-section detail view of a two-layer liner ona residual limb RL, such as in FIG. 1B, wherein the liner has an innergel-layer G that contacts the residual limb RL and an outer fabric layerF that adhered to the gel-layer G.

FIG. 2 is a font perspective view of the valve embodiment of FIG. 1,which valve embodiment comprises a one-way air outlet valve but not amanual air inlet and outlet valve.

FIG. 3 is a front view of the valve embodiment shown in FIGS. 1 and 2,with a front cover, o-ring/gasket, and spring removed to better showinternals of the valve.

FIG. 4 is a side view of the valve embodiment shown in FIGS. 1-3.

FIG. 5 is a cross-sectional side view of the embodiment shown in FIGS.1-4, and the valve is shown in the closed position.

FIG. 6 is a cross-sectional side view of the embodiment shown in FIGS.1-5, wherein the valve is shown in the open position allowing air to beexpelled.

FIG. 7 is an exploded perspective view of the valve embodiment shown inFIGS. 1-6.

FIG. 8 is an alternative embodiment of a valve stem that may be used inthe embodiment of FIGS. 1-7 and that has an o-ring in its end surface.

FIG. 9 is a cross-sectional view of an alternative embodiment of valvesystem, installed on a hard socket exterior surface over a hole, whereinthe valve system comprises a one-way outlet valve similar to theembodiment of FIGS. 1-7 and also comprises one embodiment of theinvented manual air inlet and outlet valve. In FIG. 9, the one-wayoutlet valve is shown in the closed position, which means that thepressure inside the socket well has not reached a level above theambient pressure that caused the valve stem to move outward and open theone-way valve passage. In FIG. 9, the manual valve is in the closedposition.

FIG. 10 is a cross-sectional view of the embodiment of FIG. 9, whereinthe manual valve is still in the closed position, but the one-way outletvalve has opened to allow expulsion of air from the socket well.

FIG. 11 is a cross-sectional view of the embodiment of FIGS. 9 and 10,wherein the one-way valve is in the closed position, but the manualvalve has been opened, by turning/rotating the handle portion relativeto the base portion, so that air may enter or exit the hard socket wellfrom a passageway between said handle portion and said base portion.

FIG. 12 is a side view of the embodiment of FIGS. 9-11, removed from thehard socket, wherein the base portion is shown in cross-section and themanual valve is shown closed and the one-way valve is hidden inside thehandle portion.

FIG. 13 is a side view of the embodiment of FIGS. 9-12, removed from thehard socket, wherein the base portion is shown in cross-section and themanual valve is opened, and the one-way valve is hidden inside thehandle portion.

FIG. 14 is a cross-sectional view of an alternative embodiment of theinvented valve system installed on a hard socket wall over a hole, whichvalve system comprises a manual valve in the closed position and whichdoes not comprise a one-way inlet and outlet valve.

FIG. 15 is a cross-sectional view of the embodiment of FIG. 14, whereinthe handle portion has been turned/rotated to open the manual valve, sothat air may enter or exit the hard socket well from a passagewaybetween said handle portion and said base portion.

FIG. 16 is a cross-sectional view of the embodiment of FIG. 12, viewedalong the line 16-16 in FIG. 12, this cross-section portraying positionsof tabs and ramps in a position wherein the manual valve is closed.

FIG. 17 is a cross-sectional view of the embodiment of FIGS. 12 and 13,viewed along the line 17-17 in FIG. 13, this cross-section portrayingpositions of tabs and ramps in a position wherein the manual valve isclosed.

FIG. 18 is a side view of the embodiment of FIGS. 14 and 15, with thehandle portion separated from the base portion. In FIG. 18, the externalramps of the handle portion are shown (the one near the viewer in solidlines and the one hidden from view in dashed lines) and the cooperatingbore and internal ramps of the base portion are shown in dashed lines.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the Figures, there are shown several, but not the only, embodimentsof the preferred valve system for prosthetics. FIGS. 1-8 illustrate anembodiment having only a one-way air outlet valve. FIGS. 9-11 illustratean embodiment having both a one-way air outlet valve and an embodimentof a manual valve. FIGS. 12-18 illustrate an embodiment that having onlyan embodiment of a manual valve.

Referring to embodiments that include a one-way air outlet valve, itwill be understood by one of skill in the art after reading thisapplication and viewing the drawings, that, once the air pressure insidethe hard socket (relative to the ambient pressure outside the socket)exceeds the crack pressure of the one-way valve, the invented one-way or“check” valve opens and air is expelled out through the valve. This isuseful during donning of the socket, as the insertion of the limb, orliner-covered limb, increases pressure in the socket well; the one-wayvalve system opens to generally equalize the ambient pressure and thepressure inside the socket in order to allow the donning.

After donning, when the wearer takes each step, pressure is exerteddownward on the limb, that is, toward the bottom of the socket well, andthis also increases the pressure inside the socket well. Again, thepreferred one-way valve will “crack” or “pop” to relieve this pressure,and then close when the pressure is generally equalized by cessation ofthe downward pressure of the step, and/or when the swing phase of thegait suspends the prosthetic from the residual limb/liner and a slightsuction/vacuum (relative to the ambient pressure) tends to be created inthe socket. The preferred valve is designed with a “crack pressure” inthe range of ≦3 psi differential, and more preferably 1-3 psi, or mostpreferably 1-2 psi, differential, so that, with this slightsuction/vacuum, and preferably with any pressure differential below the“set-point” (selected from the range of 1-3, or 1-2, psi positivepressure inside the socket well, that is, 1-3 or 1-2 psi above theambient pressure outside the socket well), the valve will close to notallow air into the socket through the one-way valve.

Valve system 10 is adapted to cooperate with a suspension system 100 forexternal prosthetic devices, which, as discussed in the Related Artsection, preferably include a liner that provides at least someblockage/hindrance to air passing between the socket and the liner. Asshown in FIG. 1, the preferred suspension system 100 comprises a liner103 received on a residual limb, and a hard socket 105 adapted to fitover the liner 103 and residual limb. The hard socket 105 comprises asidewall 110 defining an interior space I, wherein the sidewall 110comprises an outer surface 115 and an inner surface 120.

The liner 103 is preferably a roll-on liner, and may be of varioustypes, as discussed in the Related Art section, which provide varyingamounts of “suction.” Modern liners comprising both an inner gel layerand a textile/fabric outer layer are preferred, and the preferred valvesystem of the invention cooperates well with these liners. The valvesystem embodiments comprising a one-way air outlet valve are speciallyadapted to allow air to be expelled quietly and consistently, even asoften as every step, as may be desired with the amounts of air “leakage”experienced with fabric-covered liners.

As shown in FIGS. 2-7, valve system 10 comprises a base 20 having aninternally threaded circular bore 22 extending through the base 20. Thebase 20 is generally cylindrical in shape and is preferably fabricatedfrom a durable polymeric material or “plastic.” Alternatively, the base20 may not comprise threads, but may instead have other adaptation forjoining to the one-way valve assembly that is inserted and secured tothe base. For example, a bayonet or other latching mechanism thatanchors or secures the valve assembly into the base may be used.

The base 20 has a generally flat bottom portion 24 and a slightly curvedor rounded top portion 26 (see FIG. 4). The bottom 24 of the base 20 maybe slightly concave to mimic the contour of the outer surface 115 of thesocket in the preferred distal installation area on the socket. SeeFIGS. 1 and 1B, wherein the region labeled as “Distal Area” (or D) isindicative of the preferred, but not the only, region for attachment ofthe invented valve system. Distal attachment is preferred, wherein“distal” broadly refers to attachment of the valve system to the socketin a region below where the lower-most end of the residual limb willreach in the socket during use. Distal attachment of the valve system,however, preferably does not include attachment of the valve system atthe bottom-most point of the socket, as this location is occupied by thepost leading to the prosthetic foot and/or a distal lock that connectsto the lower-most end of the residual limb.

With the valve system 10 placed on a distal area of the hard socket 105,it may expel air as needed even when the residual limb is nearly fully,or fully, inserted into the socket. Also, in this area, the valve system10 is discreet when covered by clothing and does not protrude (as itwould from a more proximal side of the socket) to catch on clothing orother items.

After the base 20 is attached to the hard socket 105, preferably byadhesive, a hole 125 is drilled through the sidewall 110 of the hardsocket 105 via the bore 22 in the base 20, so that the hole 125generally aligns with the interior bore 22, and bore 32 and opening 62discussed below, for fluid communication between the socket well, hole125, bores 22, 32 and opening 62 to vent air out of the socket interiorI.

One may see from the drawings that the preferred valve 10 has base 20,o-ring 40, valve housing 30, stem 50 and ring/cover 60 all beingcoaxial, creating a passageway or “exit path” for air to pass throughwhen the one-way valve opens. Note that, when fully assembled, thering/cover 60 may snap into housing 30 (so that it can be easily removedfor cleaning of the system) or may be attached to housing 30 by othermethods such as adhesive.

In use, when the air pressure inside the hard socket 105 (between theliner-covered residual limb and the socket interior surface) exceeds thedesired air pressure, as further discussed below, the air will force thevalve stem 50 to move away from the opening 125 in the hard socket 105,compressing the spring 55 against the ring 60. This movement of the stem50 unseats the end 54 of the stem from the sealing surface 38, allowingair to flow around the end 54 and along the sides of the stem to theopening 62 of the ring, and out to the ambient air.

In other words, the valve system 10 comprises the valve assembly 11 thatis inserted into the base 20, which valve assembly 11 comprises a valvehousing 30 having an internal circular bore 32 with a conical sealingsurface 38 and an external threaded portion 34. The threaded portion 34on the valve housing 30 has a slightly smaller diameter than thethreaded bore 22 in the base 20, so that it may cooperate with thethreaded bore 22 in the base 20. As explained above for the base 20, thevalve housing 30 may be otherwise adapted for connecting/securing to thebase. For example, the valve housing may not have any threads and mayinstead have bayonets that are received in slots in the base when thevalve housing is inserted into and rotated in the base.

The exterior of the valve housing 30 is shown as “hex-shaped,” but othershapes may be used, such as other polygonal shapes or a cylindricalshape. The hex-shape is preferable as it may allow the technician toeasily install and tighten the valve housing or the entire assembly inthe base. Also, because the hex-shape provides a good surface to grip,it may allow the user to manually open the valve, in effect bydisassembling the valve (removing the valve assembly from the base), ifnecessary, prior to the user removing his/her residual limb from thehard socket 105.

An o-ring 40 or other seal is placed in a recess in the base 20 betweenthe base 20 and the valve housing 30. Once the valve housing 30 isthreadably or otherwise received and secured in the base 20, an airtight seal is created between the base 20 and the housing 30.

The valve assembly 11 further comprises a valve stem 50 received in thebore 32 of the housing 30. The valve stem 50 slides axially inside thebore 32 to seat against the sealing surface 38 of the housing, when thevalve is closed, and to move away from and unseat from the sealingsurface 38 when the valve is open. A spring 55 biases the valve stein 50into the closed, seated position to close the valve except when adifferential air pressure overcomes the spring 55 bias and pushes thevalve stem 50 away from the sealing surface. Spring 55 is preferably acylindrical coil compression spring, the design of which is the maindetermining factor in the crack pressure of the valve, and which one ofaverage skill can design after reading this disclosure.

The valve assembly, including the bias spring 55, are adapted so that adifferential pressure selected from a certain amount will “crack” or“pop” open the valve. In other words, the valve assembly andparticularly the spring 55 are preferably designed so that, when thepressure on the “inner side” of the valve (to the left in FIGS. 5 and 6,and typically on the inside of the socket between the liner-covered limband the interior surface of the socket at the lower end of the socket)is a certain amount above the pressure on the “outer side” of the valve(to the right in FIGS. 5 and 6, and typically outside the socket), thenthe valve will open. This “certain amount” is preferably in the range of1-3 psi, and more preferably in the range of 1-2 psi. As soon as thedifferential pressure drops (that is, as soon as the inner pressure isless than the predetermined amount, preferably 1-3 psi or 1-2 psi,higher than the outer pressure) the spring 55 will again bias the valvestem 50 to the closed, seated position. Thus, as discussed above, thevalve will open, if necessary, with each step of the wearer's gait, toallow air to vent from the socket well, and then quickly close after theair has been vented and/or when the swing portion of the gait lowers thepressure inside the socket well.

The valve stem 50 preferably has an internal bore 52 (or other hollow orrecessed end or cavity that opens to the housing bore preferably at thespring-end of the valve) that may receive air that is flowing out of thevalve in the “exit path” comprising passing around the stem, through oraround the spring, and out through the outer end of the valve (at ring60). Internal bore 52 may provide extra space for this flowing air, asit passes around or through the spring to exit the valve, thus helpingprevent unpleasant noise or venting sounds that might occur withtoo-narrow portions of the exit path. Further, various embodiments ofthe bore 52 may be advantageous during the molding or machining process,for weight reduction, and/or for cooperating with or connecting to aspring or other bias member. The preferred location of the spring 55places the spring between the flat face 53 of the valve stem 50 and theinner face 63 of the ring 60, and held there securely enough that it maybe repeatedly compressed between those surfaces and then released, whenthe valve opens and closes, respectively, without significantly shiftingfrom its preferred radially-centered position.

Further, as shown in FIG. 8, there may be an o-ring 58 or other materialon the generally conical end 54 of the stem 50, which o-ring 58 or othermaterial is preferably a softer or more flexible material, compared tothe preferred brass or hard plastic valve stem 50, for enhancing theseal between the stem 50 and the sealing surface 38. Alternatively, theentire stem 50, the conical end 54 of the stem, or another portion ofthe stem may be made of a softer plastic or other material with enhancedsealing performance.

Retaining ring 60 is a generally thin disc that is friction-fit,snapped, or otherwise secured and anchored into the bore 32 of thehousing 30 to retain the spring 55 and the stem 50 in their properpositions inside the housing. The ring 60 is preferably secured to thehousing, on ledge 39, in such a way that it will not normally come outof the housing, but that an external prosthesis technician could pry orotherwise remove it to clean the valve assembly 11 and/or replace partsof the valve assembly 11. Ring 60 has an opening 62 through which theair is expelled. Alternative ways of retaining the valve stem, spring,and/or other parts as may be desired, in the housings of the valve maybe used.

The preferred stem 50 is a hexagonal, or other polygonal shape, so thatit has multiple flat or generally flat sides 56. Therefore, the air mayflow along the end 54 of the stem and through the bore 32 of the housingin between the housing inner surface and one or more of the flat sides56. This provides multiple passages for the air, with each preferablybeing a relatively wide passage (that is, radially wider than if thestem where cylindrical inside a cylindrical housing bore), which isbelieved to be important for reducing air-venting noise. These passagesmay be said to be “spaced gaps” between the stein and the housing, inthat they are spaced apart (separated) by the edges 57 of the stem,which contact, or come very close to, contacting the bore 32 surface.These gaps, therefore, may also be called non-annular gaps ornon-annular spaces, as the gap/space between the stem and the bore ofthe housing is preferably not simply a continuous, annular space aroundthe entire stem, but rather multiple axial passageways that areseparated/spaced apart by the edges 57 that are close to, or thatcontact, the bore 32. It may also be said that, because the stem and thehousing bore are not the same shape (and particularly not the samecircumferential shape), there are multiple gaps between the stem and thehousing bore created by this difference in shape. This also places thestem 50 in the housing in a slidable arrangement, where it slidesaxially in the housing bore 32, with contact being between the edges 57of the sides 56 and the bore 32 surface, but not all the way around thecircumference of the stem. This may be important for keeping the stemfreely slidable in the bore 32 and less prone to plugging, seizingand/or becoming fouled to an extend that the valve would make morenoise.

The preferred combination of an axially-sliding stem, and a polygonal orother stem shape, that provides multiple air passages along the sides ofthe stem (which are relatively wide by being flat, recessed, orotherwise spaced from the preferably cylindrical housing bore wall) arebelieved to be at least part of the reason for the quiet, consistent,and effective operation of the valve. Also, the preferred low crackpressure that is achievable with the preferred valve with repeated,consistent operation, is believed to be important and beneficial forquiet operation and effective prosthetic suspension without large swingsin socket pressure.

Preferably, the base 20, valve housing 30, and retaining ring 60 arefabricated from a light-weight durable material, for example, Delrin™plastic; however, other materials may be used such as aluminum,titanium, nylon or other plastics. Additionally, the stem 50 may be hardplastic or brass, but also may be manufactured from other materials, forexample, including other metals, plastics, or combinations thereof.

The preferred valve system 10 is adapted to be fitted on the outsidesurface 115 of the hard socket 105, and most preferably only to theoutside surface 115. The valve system 10 is preferably attached withadhesive, by applying adhesive of types known in the field of prostheticsockets to the bottom 24 of the base and/or to the outer surface 115.Other securement means may be used, but adhesive is preferred as it hasbeen found to be reliable, easy to use, and not requiring any otherfasteners or complex or protruding parts. Preferably, no portion of thevalve system 10 extends through the socket wall, or into the interiorspace I of the hard socket 105, or contacts the inside surface 120 ofthe hard socket 105. The opening/hole 125 in the socket wall is made bydrilling or otherwise cutting through the socket wall, and this steppreferably does not include any threading or other shaping or preparingof the socket or the hole therein. Thus, the preferred valve andattachment of the valve may be used effectively with modern thin-walled,light-weight sockets. The valve system 10, in the preferred but not allembodiments, consists essentially only of, and may consist only of, abase, a valve housing, an o-ring or other seal, a stem with or withoutsupplemental sealing member or portion, a spring and a retainer ring orother closure or cover. This simple design is effective in terms ofmanufacture, installation, and operation, and has many benefits overprior art valves, including over the prior art valves that are morecomplicated, prone to plug-up, prone to make venting noise, that includeball-and-spring systems, and/or that screws/threads into the socket walland/or that resides on both sides of the socket wall. In the preferredembodiment of the invented valve system, only the base, and morepreferably only its bottom surface (24) or portions of the bottomsurface (24), is in contact with the hard socket.

Preferred embodiments may be described as a one-way pressure-controlsystem for a prosthetic hard socket, wherein the prosthetic socketcomprises a wall having an outer surface and an interior surfacedefining a well for receiving a residual limb, and said wall has a holeextending from said outer surface to said interior surface; and whereinthe valve system comprises: a base connected to said outer surface andhaving a base bore positioned over said hole in the wall; and the valvehousing being connected to said base and extending into said base boreand having a housing bore generally coaxially aligned with said basebore and in fluid communication with said hole in the socket wall, saidvalve housing having a sealing surface; a valve stein received in saidhousing bore and slidable into a first, sealed position wherein aportion of said valve stem (preferably a sealing end) seals against saidsealing surface and into a second, unsealed position away from thesealing surface; and a spring biasing the valve stem into the first,sealed position until said air pressure inside the prosthetic socketwell is at a differential pressure in the range of 1-3 psi greater thanambient pressure outside the socket, at which time the valve stem ispushed by said differential pressure into said second, unsealed positionso that air leaves the socket well by flowing through the hole andthrough the valve system. Alternatively, or in addition, the valve stemcircumference may be not the same shape as the housing borecircumference (preferably one of the two being non-circular) so that,when the valve stem is in the second, unsealed position, air flowsaround the valve stem through axial gaps between the valve stem and thehousing. Preferably, this difference in circumference/shape occurs alongthe stem side portion, which is the side portion of the stein notadapted to contact the sealing surface. The axial gaps are preferablydifferent from simply an annular space all the way around the stem, and,instead, are axial passages separated by edges that come close to, ortouch the housing bore. These edges' proximity to the housing bore wallkeeps the valve stem generally centered in the housing bore, while airflows freely past the valve stein through said axial gaps. Thus, thevalve stem may be described as being shaped so that multiple axial gapsbetween the stem and a stem housing extend along the length of the valvestem to receive air flow when the valve stem is in the second, openposition, and so that said multiple axial gaps are separated by axialedges of the valve stem that contact or come close to said stem housingand keep said valve stem generally centered in said housing. In manyembodiments, said valve stem further has a hollow end with an openingnear said spring, wherein said opening is in communication with the airpassageway(s) through the valve, providing additional space for air toflow or reside, further reducing air venting noise. The venting of airsooner (at lower differential) and with less-restricted flow, comparedto prior art vents is believed to be instrumental in reducing oreliminating the sudden, louder pop, squeak, or sputtering sounds ofprior art devices.

The invention may also comprise the methods of installing and using sucha valve system. For example, some embodiments of the invention maycomprise a method of installing a pressure-relief valve in a prostheticsocket, wherein the method comprises: providing a hard socket; providinga one-way air valve comprising a base with a base bore, a removablevalve stem housing with a housing bore, valve stem, and a spring;adhesively attaching said base to the outside of the socket; drilling ahole through the socket by inserting a drill bit through said base boreand drilling through the socket to make a hole in the wall generallycoaxially aligned with said bore in the base; inserting and securingsaid housing into the base so that the housing bore is generallycoaxially aligned with said base bore and said hole in the wall;inserting the valve stem and spring into the housing bore so that saidvalve stem slides in the housing bore to a closed position and an openposition to allow venting of air out of the socket well when pressurebuilds in the socket to a differential pressure that is greater thanambient pressure. Preferably, the method comprises no insertion of anypart of the air valve into the socket well, and no part of the air valveextends through the socket wall to reach the well. Preferably, the onlyattachment of the air valve to the socket is adhesive connection of thebase to the outer surface of the socket, and, preferably, there is nothreaded attachment of the air valve to the socket.

Referred now to FIGS. 9-11, an alternative embodiment comprises a valveunit 110 that includes a manual valve as well as a one-way valve. Fromthe cross-sectional view of FIGS. 9 and 10, one may see that the one-wayvalve assembly 111 is threadably connected to a handle 120 thatgenerally serves the same purpose relative to the valve assembly 111 asbase 20 serves to valve assembly 11, however, handle 120 is not directlyattached to the socket. Instead, handle 120 is preferably expanded indiameter and/or provided with a flared outer circumference portion, orgrip portion 121, of hexagonal or other polygonal shape, to provide theuser a larger, and preferably easily-rotatable grip surface whenoperating the manual valve. Further, instead of having a flat bottom (orrear surface) that attaches directly to the hard socket, handle 120 hasa rear protrusion 123 that is received in and operatively connected tobase 170. It is base 170 that is directly connected to the socket,preferably in the same way as discussed above for the base 20, that is,by adhesive. As discussed in detail for base 20, base 170 preferablydoes not connect to, or include, any structure that reaches through thesocket wall or into the socket well, but rather firmly isglued/adhesively attached to a distal region of the socket exterior wallsurface. As discussed with base 20, a hole (H in FIGS. 9-11, 14, 15) maybe drilled through the socket wall after attachment of the base 170 tothe socket, or by other means or steps. As may be understood fromdiscussion of such an attachment, it will be understood that such anattachment will be effective for a thin-walled socket and will beconvenient and simple compared to more complex mechanisms that requirefasteners or clamps or other structure both on the inside and theoutside of the wall.

The operative connection of handle 120 (preferably with its valveassembly 111 including valve casing 111′) and the base 170 allow saidhandle and base to form a manual valve system that is substantially orentirely independent of the operation of the one-way valve. Handle 120is preferably rotatable relative to base 170, and is preferably coaxialwith the base 170. Upon rotation, in one direction, the handle 120 moveclose to the base 170 to seal against the base, and, upon rotation in anopposite direction, the handle 120 moves out away from the base 170 tocreate a space between the handle and base that allows air flow betweenthe handle and base. In the manual valve closed position, shown in FIGS.9 and 10, the rear surface 124 of the handle grip portion 121 seals tothe front flange 172 of the base 170, most preferably by means of ano-ring or gasket 174 provided in a groove on the flange 172 or otherwiseretained on the flange. One may see in FIGS. 9 and 10 that the one-wayvalve assembly 111 may operate as described above for valve assembly 11(closed in FIG. 9 and “popped” open in FIG. 10) when the manual valvesystem is closed, that is, when the handle 120 and base 170 are inclosed, sealed condition. When the manual valve is closed, the onlypassageway possible for air exit through the valve 110 is to pop theone-way valve. It is noteworthy that, whether the manual valve isclosed, air may pass through the base 170 (through bore 176) and throughthe rear aperture 125 in the rear protrusion 123 to reach the one-wayvalve stem 150, and, upon opening the stem 150 (as discussed above forstem 50), the air may flow around the stem and out of the one-way valveassembly via opening 162. When the manual valve is opened, as discussedbelow, air will flow out via the space/gap between the base 170 and thehandle 120, rather than popping the one-way valve, or will flow in viasaid space/gap, depending upon the relative pressures inside the socketand outside the socket.

The preferred method of operating the manual valve is by rotation of thehandle 120 relative to the base 170, wherein cooperating structure ofthe handle and base serves to distance the handle 120 from the base 170upon at least a portion of said rotation. Said cooperating structurepreferably comprises at least one ramp on either of said handle 120 orsaid base 170 and at least one riding member on the other of said handleor base, wherein relative rotation of the handle and base allow theriding member to “ride” or slide along the ramp to change the relativeaxial location of the handle and the base. Said at least one ramp isslanted so that rotation preferably in the range of 30-270 degrees (morepreferably 30-90 degrees and most preferably 30-70 degrees) distancesthe handle from the base enough to unseal the two from each other forair flow there-between. The riding member may be a protrusion or ramp.When the riding member is itself a ramp, one may consider the ramps tocooperate as do threads, but only threads that allow less than a fullrotation. In other words, the handle may be unscrewed from the base lessthan a full rotation, so that the handle movement has an axial componentto move the handle slightly out from the base. The rotational operationof the valve, in each of the opening direction and the closingdirection, preferably is only a partial rotation (30-270 degrees, morepreferably, a partial rotation in the range of 30-90 and, mostpreferably 30-60, degrees). Opening by rotation in the range of about30-60 degrees, and closing in the opposite direction by rotation thesame amount (also in the range of 30-60 degrees) is particularlycomfortable and easy to perform, as the user simple “twists” the handlea short distance one way and then the other. The especially-preferredoperation, therefore, is more like a quick twist than anscrewing/unscrewing a threaded system.

In the especially-preferred embodiment, two ramps 127, 129 are provided180 degrees apart on the outer, cylindrical surface 134 of the rearprotrusion 123. Two tabs 177, 179 are provided on the interiorcylindrical surface of the bore through base 170, and extending betweenthe tabs 177 179 on said interior surface are ramps 181, 182. When thepreferred handle 120 is rotated clockwise relative to the preferred base170, ramps 181, 182 ride along ramps 127, 129 to pull the handle closerto the base, as if the handle were being screwed into the base, to anextent that seals the handle to the base at o-ring/gasket 174. When thepreferred handle 120 is rotated counterclockwise relative to thepreferred base 170, ramps 181, 182 ride in the opposite direction alongramps 127, 129 to allow the handle to be slightly distanced from thebase, as if the handle were being unscrewed part-way from the base, toan extent that unseals the handle from the base at o-ring/gasket 174. Inthis open condition, as shown in FIG. 11, air may flow out from thesocket or into the socket through the space S (space S shown in FIG. 15)between the handle and the base.

Tabs 177, 179 move, during said rotation, preferably between limitingstructure (L, FIGS. 16 and 17) that is preferably at the ends of ramps127, 129. The tabs 177, 179 may move between said limits L in areas ofthe outer surface 134 that is recessed relative to the areas upon whichthe ramps 127, 129 are located.

The handle 120 and base 170 are preferably connected and disconnectableby means of a snap system, wherein the handle snaps into the base andthen is rotatable relative to the base. In the preferred embodiments,the handle and base snap together by the handle being positionablerelative to the base in a position wherein portions of the ramps 181,182 and/or tabs 177, 179 snap over slightly-protruding structure on theouter, cylindrical surface 134 to a point wherein the handle is base isheld on the handle. Preferably, spaces (significantly wider than thetabs 177, 179) exist between the two ramps 127, 129 on the surface 134(said relatively recessed areas mentioned above) and, as the two tabs177, 179 into those recessed spaces, slide, portions of ramps 181, 182also slide into said spaces and portions of ramps 181, 182 snap over thecooperating ramps 127, 129 on the handle rear protrusion outer surface134. There may be an optional slight protrusion at the entry of therecessed spaces over which the tabs may snap. When the tabs slide intothe recessed spaces and the ramps 181, 182 snap over ramps 127, 129, thebase ends up in a position relative to the handle wherein the base isclose to, and generally tight against the handle, and the manual valveis therefore closed. In this position, the handle and base have snappedtogether, and are in position for the ramps to slide along each other toopen the manual valve when the handle is twisted counterclockwiserelative to the base. If substantial pulling on the handle wereconducted, the handle might snap off of the base, this is unlikely tohappen unintentionally, as only twisting is necessary, and not pullingor pushing, to open and close the manual valve.

In FIGS. 12-15, and 18, there is shown yet another embodiment 210,wherein the valve system 210 comprises only a manual valve and not aone-way air outlet valve. The valve system 210 may be the same as thatdescribed above for FIGS. 9-10, but, instead of the handle having a borethere-through that receives and cooperates with a one-way valveassembly, the handle 120′ is closed at its front (toward the right inFIGS. 12-15, and 18. The handle may still have a front, central indent,as portrayed in FIGS. 14 and 15, but this is preferably simply anoptional indent or depression. As in the embodiment of FIGS. 9-11, theembodiments of FIGS. 12-15 and 18 allows air to flow out of, and into,the socket, by flowing axially through a portion of the passageway (theportion in the base) and radially (through the space between the flangeof the base and the rear side of the rear protrusion 123 of the handle.

The hard socket is preferably chosen from many conventional rigidprosthetic sockets currently available on the market. The suspensionand/or connection systems for connection the hard socket may includelocks, straps, and other mechanisms that are available on the market.

Although this invention has been described above with reference toparticular means, materials and embodiments, it is to be understood thatthe invention is not limited to these disclosed particulars, but extendsinstead to all equivalents within the broad scope of the followingclaims.

1. A pressure-control system for a prosthetic hard socket, thepressure-control system comprising: a prosthetic hard socket comprisinga wall having an outer surface and an interior surface defining a wellfor receiving a residual limb, and said wall having a hole extendingfrom said outer surface to said interior surface; and an air valvecomprising: a base on said outer surface of the hard socket over saidhole in the wall; a handle connected to said base and manually rotatablerelative to the base; and an air passageway through said base and saidhandle that is blocked when the handle is rotated relative to the baseto a closed position, and that is unblocked for air flow through thevalve and the hole into and out of the hard socket, when the handle isrotated relative to the base to an open position; and wherein the airvalve comprises at least one stop adapted to limit rotation of saidhandle relative to the base to a portion of a full rotation, the portionbeing in the range of 30-90 degrees, so that the handle rotates onlysaid portion of a full rotation when moving from the closed to the openposition.
 2. A pressure control system as in claim 1, wherein, when thehandle is rotated said portion of a full rotation to the open position,the handle is distanced from the base to form a radial gap between saidbase and said handle.
 3. A pressure control system as in claim 2,wherein the handle is distanced from the base by rotating into said openposition by means of ramps provided on the handle sliding on cooperatingramps provided on the base.
 4. A pressure control system as in claim 3,wherein said ramps provided on the base are slanted so that the handlerotating said portion of a full rotation moves the handle axially outfrom the base to form said radial gap.